fluoride

American  

[floor-ahyd, flawr-, flohr-] / ˈflʊər aɪd, ˈflɔr-, ˈfloʊr- /

noun

Chemistry.

fluorides plural

1. a salt of hydrofluoric acid consisting of two elements, one of which is fluorine, as sodium fluoride, NaF.

2. a compound containing fluorine, as methyl fluoride, CH 3 F.

---

fluoride British  

/ ˈflʊəˌraɪd /

noun

1. any salt of hydrofluoric acid, containing the fluoride ion, F ^–

2. any compound containing fluorine, such as methyl fluoride

---

fluoride Scientific  

/ flr′īd′ /

1. A compound containing fluorine and another element or radical. Fluorine combines readily with nearly all the other elements, except the noble gases, to form fluorides. In some countries, fluoride is added to the drinking water as a preventive measure against tooth decay.

---

fluoride Cultural  

1. Any of a number of naturally occurring compounds of the element fluorine. Fluorides have been found to be effective in preventing tooth decay and are routinely added to drinking water in most jurisdictions.

---

Other Word Forms

Noun Inflected Forms

• fluorides
  plural

Etymology

Origin of fluoride

First recorded in 1820–30; fluor- + -ide ( def. )

Compare meaning

How does fluoride compare to similar and commonly confused words? Explore the most common comparisons:

• fluorine vs. fluoride

Explanation

Fluoride is that ingredient in toothpaste that keeps tooth enamel strong and helps prevent cavities. Small amounts of fluoride are also present in tap water and certain foods and beverages. Fluoride is a naturally occurring mineral widely recognized for its oral health benefits. Fluoride is often added to toothpaste and mouthwash to help prevent tooth decay by making the enamel more resistant to acid attacks from bacteria and sugars. That’s why some communities add it to their water supply systems: Regular exposure to fluoride is generally considered important in maintaining oral hygiene. Fluoride is also found in tea, seafood, and some fruits and vegetables. Now that’s toothsome!

Example Sentences

See Examples For:

fluoride fluorides

Unlike conventional fluoride products, however, the new gel contains no fluoride.

From Science Daily ● Jul. 23, 2026

Fire Department said it detected low-levels of toxic hydrogen fluoride on the second day of the fire, which can be a byproduct of burning lithium-ion batteries.

From Los Angeles Times ● Jun. 30, 2026

Kairos uses molten fluoride salt as a coolant, allowing it to operate at low pressures and high temperatures, and it also has a smaller demonstration reactor under construction in Oak Ridge.

From The Wall Street Journal ● Apr. 23, 2026

“However, this is still not likely as there was at least some sodium fluoride which would help preserve the sample.”

From Los Angeles Times ● Mar. 19, 2026

It is true that Washington lost most of his own teeth, which was hardly unusual in the days before modern dentists and fluoride toothpaste.

From "In the Shadow of Liberty" by Kenneth C. Davis

There are four main chemical approaches that are commonly used to create sulfoximines, sulfonimidoyl fluorides and sulfonimidamides.

From Science Daily ● Jan. 22, 2024

Compounds with oxygen are prepared by replacing fluorine atoms in the xenon fluorides with oxygen.

From Textbooks ● Feb. 14, 2019

Such wastes as chlorides, chlorates, salts of phosphonic acid, fluorides, and arsenic had been discharged from the Rocky Mountain Arsenal during the years of its operation by the Army Chemical Corps.

From The New Yorker ● Jan. 3, 2017

In the years since, fluorides have been proved to reduce the rate of tooth decay in adults as well as in children.

From New York Times ● Jan. 23, 2012

Chlorides, chlorates, salts of phosphonic acid, fluorides, and arsenic had been discharged from the Rocky Mountain Arsenal into holding ponds during the years of its operation.

From "Silent Spring" by Rachel Carson